Hi all,

According to my records exactly to the month, my Dexcool is 5 years old and have put on less than 40k miles since then. When I put it in back then, I used distilled water both for the flush and the back-fill of coolant.

My question is the following: In your experience how hard is the deadline of 5 years/100,000 miles for replacing it?

I'd like to delay the flushing and refill until the spring if I can. I tested the freeze point and it is still where it was, -34'F if I remember correctly. I was thinking about getting some pH tester strips to confirm that it is still OK too.

What are your thoughts?

 

I hate to admit it but my 2006 G6 GTP I bought new still has the original Dexcool. It is still bright orange and have never had to put a hose or water pump on or fix a leak. I have only added Prestone Dexcool (already diluted) to top off as required. I keep telling myself to change it. I think you will be just fine. The G6 does have the pressurized overflow tank where the Blazer does not.

 

Thanks Les.

Yeah I'm thinking it will.be fine.

I got some test strips that test concentration and pH for the coolant, and the contamination in the brake fluid.

The current coolant, and brake fluid passed. I got these at NAPA. (Phoenix Brand)

https://brakebleeder.com/products/co...id-test-strips

 

Here are the results of the tests I did with the strips.


Freeze/Boil point about equivalent to 45% concentration. I tested with a refractometer that I deem more accurate and it tested at 50%, i.e., -34'F.



pH test of the coolant about 9, well above threshold for replacement of 7. The one thing that is confusing is that according to a Texaco tech document, the stand-alone pH of Dexcool is 8.3. Even if I allow for wide error bars, I figure I'm fine. (https://www.taligentx.com/passat/inf...fe_Coolant.pdf)



Brake contamination about 10 ppm, a factor of ten below the threshold. I had just added some fresh fluid though.

 

I say if it's that old just flush and replace, but it looks like it should be okay until next year.

 

youve hit on all the points except corrosion resistance.

Water is rather nasty to metals...

 

Good point. I'll double check on that. Thanks.